power line communication – free thesis
This thesis is about power-line communication over the low-voltage grid
The communication flow of today is very high. Many applications are operating at high speed and a fixed connection is often preferred. If the power utilities could supply communication over the power-line to the costumers it could make a tremendous breakthrough in communications. Every household would be connected at any time and services being provided at real-time. Using the power-line as a communication medium could also be a cost-effective way compared to other systems because it uses an existing infrastructure, wires exists to every household connected to the power-line network. The deregulated market has forced the power utilities to explore new markets to find new business opportunities, which have increased the research in power-line communications the last decade. The research has initially been focused on providing services related to power distribution such as load control, meter reading, tariff control, remote control and smart homes. These value-added services would open up new markets for the power utilities and hence increase the profit. The moderate demands of these applications make it easier to obtain reliable communication. Firstly, the information bit rate is low, secondly, they do not require real-time performance. During the last years the use of Internet has increased. If it would be possible to supply this kind of network communication over the power-line, the utilities could also become communication providers, a rapidly growing market. On the contrary to power related applications, network communications require very high bit rates and in some cases realtime responses are needed (such as video and TV). This complicates the design of a communication system but has been the focus of many researchers during the last years. Systems under trial exist today that claim a bit rate of 1 Mb/s, but most commercially available systems use low bit rates, about 10-100 kb/s, and provides low-demanding services such as meter reading. The power-line was initially designed to distribute power in an efficient way, hence it is not adapted for communication and advanced communication methods are needed.2 Today’s research is mainly focused on increasing the bit rate to support high-speed network applications. This thesis is about communication on the power-line (on the low-voltage grid). Section 1.1 gives a general description of power-line communications. Section 1.2 explains some preliminaries needed in digital communications and Section 1.3 describes the power-line channel, its characteristics, problems and limitations, and also serves as a survey of current research. Finally Section 1.4 gives an outline of the rest of this thesis. Other introductory descriptions on power-line communications are given in , , and . Reference also studies new business opportunities for the power utilities and reports research on coming technology.